Simulation of Surface Plasmon Coupled Conjugate Polymer for Polymer Light-Emitting Diodes

Since 1977, conjugated polymers have received attention as materials for display devices with a low-cost solution process, but the low efficiency of these materials has been considered as a drawback which should be overcome. Nowadays metal nanoparticles are inserted on the display device´s cathode to overcome the low efficiency of the materials through the enhanced coupling between the Localized surface plasmon resonance (LSPR) and exciton in emitting material . In our previous work, conjugated polymer with an imprinted regular Ag-dot-array structure showed a 2.7-fold improvement of integrated photoluminescence (PL) intensity , but the result was not optimized. Therefore, in this study, we calculated the Ag-dot-array absorbance-peak shift in detail using finite-difference time-domain (FDTD) simulation and found the absorbance peak location which maximized photoluminescence (PL) intensity, depending on various Ag dot condition. The resulting information was applied to the previous structure . Thus, we reduced the trial and error of finding the optimized absorbance peak location and the imprint processing costs. The most important parameter of the Ag-dot-array absorbance peak was the lattice constant. Furthermore, we proved the indium tin oxide (ITO) waveguide effect in our structure using FDTD.